Society for Popular Astronomy

If a laser is mounted as a piece of scientific equipment - ie not hand held - then different rules apply. At a certain establishment in Berkshire they use lasers to initiate nuclear fusion - they are a bit more powerful than 1 mW!! Mounted on your telescope may appear to be covered by this proviso. ...

I have a PST which I double-stack - I have been wanting to get a DMK21, your results have inspired me enormously - thanks!!

Us solar observers just laugh at light pollution!!

brian livesey wrote: I'm no expert, but is water vapour really a "gas"?

Yes water vapour is quite gaseous.

Whenever I meet a global warming panicker, I always ask what is the most important greenhouse gas?! None of them have got it right yet.

As no one here seems to have any idea - the MOST IMPORTANT greenhouse gas is WATER VAPOUR. Because of the water vapour in the atmosphere, the Earth´s mean temperature is maintained PRESENTLY at +15C. Take out the water vapour and it drops to -15C - which has happened in the past - when the entire pl...

peteuplink wrote: Took me ages to convert from VHS to DVD

You do realise that Betamax is technically the best system!

Ever since the earth formed its climate has ALWAYS been changing. The question is what is causing this change - is it anything at all to do with CO2 levels or do changes in CO2 levels actually follow changes in climate rather than cause them, as some climatologists believe to be the case. And what i...

peteuplink wrote:Took me ages to convert from VHS to DVD

Betamax FOR EVER !!!!!

Am I right in saying that 1 degree is approximately 70 miles? Depends what sort of miles you are talking about. If you start thinking about Nautical Miles it gets a lot easier (again approximately as there are slight variations) but 1 deg =(approx.) 60 Nautical miles Ian Isn´t 1 degree of latitude ...

I find the vitriol being thrown after the death of a good man all rather sad.

David Frydman wrote: make the Earth flat,

Isn´t it ??

David Frydman wrote:Also at Imperial College theoretically it is possible to bend light so that an object disappears.

Didn´t ´Q´ do that with a car in one of the Bond movies?

I had my first view of Albireo (beta Cygni) tonight. Wow it knocked my socks off, beautiful bright, wide double, the two stars of distinctly different colours (orange and blue). Currently very close to the zenith at civilised observing times. Recommended.

This sort of thing is always a problem. Manufacturers can and do use a mix of standards. I wanted some additional screws for my Stellarvue clamshell - an email to Vic Maris got me the required info - some obscure imperial size thread. A quick google found me a supplier in the UK - only pennies each....